GO FOR DRAGON CLAW! I've got an Garchomp too and it's Dragon Claw works awesomly with Swords Dance! Outrage will confuse it and sometimes its not too great if you want to use other moves in battle for type advantages.
Garchomp @ dragon claw
Dragon Rush/Stone Edge
Dragon Claw @ Swords dance is awesome since S-Dance increases attack stat. two times in a row.
Earthquake for those annoying electrick types and others (Powerful too)
Dragon rush (Extremly powerful with S-Dance) or Stone Edge to smash those birds! (Awesome with S-Dance too)
Hope I helped!